A relay is an electrically operated switch. When an electrical current is applied to the coil of a relay, it creates a magnetic field that activates the switch. In a 12-volt relay, the coil is energized by a 12V DC (direct current) signal. These relays typically consist of an electromagnet, an armature, contacts, and a spring mechanism. When the relay is energized, the electromagnet attracts the armature, which in turn closes or opens the contacts, allowing current to flow through the circuit or cutting it off.

    12-volt relays are used extensively in automotive applications, where they control high-power components such as lights, fans, and motors, which require higher currents than a typical control circuit can handle. They are also crucial in household appliances, industrial control systems, and even home security systems. The ability to switch large currents with a small control signal makes relays incredibly versatile and essential in modern electrical engineering.